(1) Field of the Invention
This invention relates generally to the deployment of underwater cable and the attachment of tethered transducer to such cable as the cable is being deployed.
(2) Description of the Prior Art
As used herein, the term "transducer" includes hydrophones, pingers and other electroacoustic devices.
One characteristic of oceanographic communication via underwater cable is that the cable tends to twist and move causing the tethered transducer or electroacoustic transducer riser cable to become twisted around the trunk or tow cable. Various devices have been employed to reduce this propensity for the riser cable of the transducer being ensnared by the trunk or tow cable, including swivel connectors of the type sometimes used with chains and hoses or the like. See for example prior art U.S. Pat. No. 2,519,460 wherein a swivel is provided between lengths of chain. Such a device suffers from the disadvantage that it cannot be applied to a continuous trunk or tow cable being deployed at sea. U.S. Pat. No. 3,107,110 illustrates a swivel suitable for use with a continuous hose. However, this prior art swivel device suffers from the disadvantage that it must be clamped to the elongated hose or pipe. As a result of such cable construction being made up of wire strands wrapped in a helical fashion inside the outer cable covering the cable tends to twist and turn. Furthermore tension loads in the cable tend to reduce the outer diameter of the cable cover with the result that such prior art swivel devices tend to slip along the cable in the underwater environment. Deployment constraints also prevent the adaptation of prior art solutions to gripping such cable, and the present invention seeks to provide a solution to these problems that not only avoids these cable construction constraints, but which also provides a conveniently attachable means for securing the tethered transducers to selected points along the cable while the cable is being deployed at sea.